drivers/usb/gadget/f_uac1.c - maze/linux - Git at Google

 /*
  * f_audio.c -- USB Audio class function driver
   *
  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
  * Copyright (C) 2008 Analog Devices, Inc
  *
  * Enter bugs at http://blackfin.uclinux.org/
  *
  * Licensed under the GPL-2 or later.
  */

 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/atomic.h>

 #include "u_uac1.h"

 #define OUT_EP_MAX_PACKET_SIZE	200
 static int req_buf_size = OUT_EP_MAX_PACKET_SIZE;
 module_param(req_buf_size, int, S_IRUGO);
 MODULE_PARM_DESC(req_buf_size, "ISO OUT endpoint request buffer size");

 static int req_count = 256;
 module_param(req_count, int, S_IRUGO);
 MODULE_PARM_DESC(req_count, "ISO OUT endpoint request count");

 static int audio_buf_size = 48000;
 module_param(audio_buf_size, int, S_IRUGO);
 MODULE_PARM_DESC(audio_buf_size, "Audio buffer size");

 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);

 /*
  * DESCRIPTORS ... most are static, but strings and full
  * configuration descriptors are built on demand.
  */

 /*
  * We have two interfaces- AudioControl and AudioStreaming
  * TODO: only supcard playback currently
  */
 #define F_AUDIO_AC_INTERFACE	0
 #define F_AUDIO_AS_INTERFACE	1
 #define F_AUDIO_NUM_INTERFACES	2

 /* B.3.1  Standard AC Interface Descriptor */
 static struct usb_interface_descriptor ac_interface_desc __initdata = {
 	.bLength =		USB_DT_INTERFACE_SIZE,
 	.bDescriptorType =	USB_DT_INTERFACE,
 	.bNumEndpoints =	0,
 	.bInterfaceClass =	USB_CLASS_AUDIO,
 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
 };

 DECLARE_UAC_AC_HEADER_DESCRIPTOR(2);

 #define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
 /* 1 input terminal, 1 output terminal and 1 feature unit */
 #define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
 	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
 /* B.3.2  Class-Specific AC Interface Descriptor */
 static struct uac1_ac_header_descriptor_2 ac_header_desc = {
 	.bLength =		UAC_DT_AC_HEADER_LENGTH,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_HEADER,
 	.bcdADC =		__constant_cpu_to_le16(0x0100),
 	.wTotalLength =		__constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
 	.bInCollection =	F_AUDIO_NUM_INTERFACES,
 	.baInterfaceNr = {
 		[0] =		F_AUDIO_AC_INTERFACE,
 		[1] =		F_AUDIO_AS_INTERFACE,
 	}
 };

 #define INPUT_TERMINAL_ID	1
 static struct uac_input_terminal_descriptor input_terminal_desc = {
 	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
 	.bTerminalID =		INPUT_TERMINAL_ID,
 	.wTerminalType =	UAC_TERMINAL_STREAMING,
 	.bAssocTerminal =	0,
 	.wChannelConfig =	0x3,
 };

 DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);

 #define FEATURE_UNIT_ID		2
 static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
 	.bLength		= UAC_DT_FEATURE_UNIT_SIZE(0),
 	.bDescriptorType	= USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype	= UAC_FEATURE_UNIT,
 	.bUnitID		= FEATURE_UNIT_ID,
 	.bSourceID		= INPUT_TERMINAL_ID,
 	.bControlSize		= 2,
 	.bmaControls[0]		= (UAC_FU_MUTE | UAC_FU_VOLUME),
 };

 static struct usb_audio_control mute_control = {
 	.list = LIST_HEAD_INIT(mute_control.list),
 	.name = "Mute Control",
 	.type = UAC_FU_MUTE,
 	/* Todo: add real Mute control code */
 	.set = generic_set_cmd,
 	.get = generic_get_cmd,
 };

 static struct usb_audio_control volume_control = {
 	.list = LIST_HEAD_INIT(volume_control.list),
 	.name = "Volume Control",
 	.type = UAC_FU_VOLUME,
 	/* Todo: add real Volume control code */
 	.set = generic_set_cmd,
 	.get = generic_get_cmd,
 };

 static struct usb_audio_control_selector feature_unit = {
 	.list = LIST_HEAD_INIT(feature_unit.list),
 	.id = FEATURE_UNIT_ID,
 	.name = "Mute & Volume Control",
 	.type = UAC_FEATURE_UNIT,
 	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
 };

 #define OUTPUT_TERMINAL_ID	3
 static struct uac1_output_terminal_descriptor output_terminal_desc = {
 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
 	.bDescriptorType	= USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
 	.bTerminalID		= OUTPUT_TERMINAL_ID,
 	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
 	.bAssocTerminal		= FEATURE_UNIT_ID,
 	.bSourceID		= FEATURE_UNIT_ID,
 };

 /* B.4.1  Standard AS Interface Descriptor */
 static struct usb_interface_descriptor as_interface_alt_0_desc = {
 	.bLength =		USB_DT_INTERFACE_SIZE,
 	.bDescriptorType =	USB_DT_INTERFACE,
 	.bAlternateSetting =	0,
 	.bNumEndpoints =	0,
 	.bInterfaceClass =	USB_CLASS_AUDIO,
 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
 };

 static struct usb_interface_descriptor as_interface_alt_1_desc = {
 	.bLength =		USB_DT_INTERFACE_SIZE,
 	.bDescriptorType =	USB_DT_INTERFACE,
 	.bAlternateSetting =	1,
 	.bNumEndpoints =	1,
 	.bInterfaceClass =	USB_CLASS_AUDIO,
 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
 };

 /* B.4.2  Class-Specific AS Interface Descriptor */
 static struct uac1_as_header_descriptor as_header_desc = {
 	.bLength =		UAC_DT_AS_HEADER_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_AS_GENERAL,
 	.bTerminalLink =	INPUT_TERMINAL_ID,
 	.bDelay =		1,
 	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
 };

 DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);

 static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
 	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
 	.bFormatType =		UAC_FORMAT_TYPE_I,
 	.bSubframeSize =	2,
 	.bBitResolution =	16,
 	.bSamFreqType =		1,
 };

 /* Standard ISO OUT Endpoint Descriptor */
 static struct usb_endpoint_descriptor as_out_ep_desc  = {
 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bEndpointAddress =	USB_DIR_OUT,
 	.bmAttributes =		USB_ENDPOINT_SYNC_ADAPTIVE
 				| USB_ENDPOINT_XFER_ISOC,
 	.wMaxPacketSize =	__constant_cpu_to_le16(OUT_EP_MAX_PACKET_SIZE),
 	.bInterval =		4,
 };

 /* Class-specific AS ISO OUT Endpoint Descriptor */
 static struct uac_iso_endpoint_descriptor as_iso_out_desc __initdata = {
 	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
 	.bDescriptorSubtype =	UAC_EP_GENERAL,
 	.bmAttributes = 	1,
 	.bLockDelayUnits =	1,
 	.wLockDelay =		__constant_cpu_to_le16(1),
 };

 static struct usb_descriptor_header *f_audio_desc[] __initdata = {
 	(struct usb_descriptor_header *)&ac_interface_desc,
 	(struct usb_descriptor_header *)&ac_header_desc,

 	(struct usb_descriptor_header *)&input_terminal_desc,
 	(struct usb_descriptor_header *)&output_terminal_desc,
 	(struct usb_descriptor_header *)&feature_unit_desc,

 	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
 	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
 	(struct usb_descriptor_header *)&as_header_desc,

 	(struct usb_descriptor_header *)&as_type_i_desc,

 	(struct usb_descriptor_header *)&as_out_ep_desc,
 	(struct usb_descriptor_header *)&as_iso_out_desc,
 	NULL,
 };

 /*
  * This function is an ALSA sound card following USB Audio Class Spec 1.0.
  */

 /*-------------------------------------------------------------------------*/
 struct f_audio_buf {
 	u8 *buf;
 	int actual;
 	struct list_head list;
 };

 static struct f_audio_buf *f_audio_buffer_alloc(int buf_size)
 {
 	struct f_audio_buf *copy_buf;

 	copy_buf = kzalloc(sizeof *copy_buf, GFP_ATOMIC);
 	if (!copy_buf)
 		return ERR_PTR(-ENOMEM);

 	copy_buf->buf = kzalloc(buf_size, GFP_ATOMIC);
 	if (!copy_buf->buf) {
 		kfree(copy_buf);
 		return ERR_PTR(-ENOMEM);
 	}

 	return copy_buf;
 }

 static void f_audio_buffer_free(struct f_audio_buf *audio_buf)
 {
 	kfree(audio_buf->buf);
 	kfree(audio_buf);
 }
 /*-------------------------------------------------------------------------*/

 struct f_audio {
 	struct gaudio			card;

 	/* endpoints handle full and/or high speeds */
 	struct usb_ep			*out_ep;

 	spinlock_t			lock;
 	struct f_audio_buf *copy_buf;
 	struct work_struct playback_work;
 	struct list_head play_queue;

 	/* Control Set command */
 	struct list_head cs;
 	u8 set_cmd;
 	struct usb_audio_control *set_con;
 };

 static inline struct f_audio *func_to_audio(struct usb_function *f)
 {
 	return container_of(f, struct f_audio, card.func);
 }

 /*-------------------------------------------------------------------------*/

 static void f_audio_playback_work(struct work_struct *data)
 {
 	struct f_audio *audio = container_of(data, struct f_audio,
 					playback_work);
 	struct f_audio_buf *play_buf;

 	spin_lock_irq(&audio->lock);
 	if (list_empty(&audio->play_queue)) {
 		spin_unlock_irq(&audio->lock);
 		return;
 	}
 	play_buf = list_first_entry(&audio->play_queue,
 			struct f_audio_buf, list);
 	list_del(&play_buf->list);
 	spin_unlock_irq(&audio->lock);

 	u_audio_playback(&audio->card, play_buf->buf, play_buf->actual);
 	f_audio_buffer_free(play_buf);
 }

 static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_audio *audio = req->context;
 	struct usb_composite_dev *cdev = audio->card.func.config->cdev;
 	struct f_audio_buf *copy_buf = audio->copy_buf;
 	int err;

 	if (!copy_buf)
 		return -EINVAL;

 	/* Copy buffer is full, add it to the play_queue */
 	if (audio_buf_size - copy_buf->actual < req->actual) {
 		list_add_tail(&copy_buf->list, &audio->play_queue);
 		schedule_work(&audio->playback_work);
 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
 		if (IS_ERR(copy_buf))
 			return -ENOMEM;
 	}

 	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
 	copy_buf->actual += req->actual;
 	audio->copy_buf = copy_buf;

 	err = usb_ep_queue(ep, req, GFP_ATOMIC);
 	if (err)
 		ERROR(cdev, "%s queue req: %d\n", ep->name, err);

 	return 0;

 }

 static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
 {
 	struct f_audio *audio = req->context;
 	int status = req->status;
 	u32 data = 0;
 	struct usb_ep *out_ep = audio->out_ep;

 	switch (status) {

 	case 0:				/* normal completion? */
 		if (ep == out_ep)
 			f_audio_out_ep_complete(ep, req);
 		else if (audio->set_con) {
 			memcpy(&data, req->buf, req->length);
 			audio->set_con->set(audio->set_con, audio->set_cmd,
 					le16_to_cpu(data));
 			audio->set_con = NULL;
 		}
 		break;
 	default:
 		break;
 	}
 }

 static int audio_set_intf_req(struct usb_function *f,
 		const struct usb_ctrlrequest *ctrl)
 {
 	struct f_audio		*audio = func_to_audio(f);
 	struct usb_composite_dev *cdev = f->config->cdev;
 	struct usb_request	*req = cdev->req;
 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
 	u16			len = le16_to_cpu(ctrl->wLength);
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u8			con_sel = (w_value >> 8) & 0xFF;
 	u8			cmd = (ctrl->bRequest & 0x0F);
 	struct usb_audio_control_selector *cs;
 	struct usb_audio_control *con;

 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
 			ctrl->bRequest, w_value, len, id);

 	list_for_each_entry(cs, &audio->cs, list) {
 		if (cs->id == id) {
 			list_for_each_entry(con, &cs->control, list) {
 				if (con->type == con_sel) {
 					audio->set_con = con;
 					break;
 				}
 			}
 			break;
 		}
 	}

 	audio->set_cmd = cmd;
 	req->context = audio;
 	req->complete = f_audio_complete;

 	return len;
 }

 static int audio_get_intf_req(struct usb_function *f,
 		const struct usb_ctrlrequest *ctrl)
 {
 	struct f_audio		*audio = func_to_audio(f);
 	struct usb_composite_dev *cdev = f->config->cdev;
 	struct usb_request	*req = cdev->req;
 	int			value = -EOPNOTSUPP;
 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
 	u16			len = le16_to_cpu(ctrl->wLength);
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u8			con_sel = (w_value >> 8) & 0xFF;
 	u8			cmd = (ctrl->bRequest & 0x0F);
 	struct usb_audio_control_selector *cs;
 	struct usb_audio_control *con;

 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
 			ctrl->bRequest, w_value, len, id);

 	list_for_each_entry(cs, &audio->cs, list) {
 		if (cs->id == id) {
 			list_for_each_entry(con, &cs->control, list) {
 				if (con->type == con_sel && con->get) {
 					value = con->get(con, cmd);
 					break;
 				}
 			}
 			break;
 		}
 	}

 	req->context = audio;
 	req->complete = f_audio_complete;
 	len = min_t(size_t, sizeof(value), len);
 	memcpy(req->buf, &value, len);

 	return len;
 }

 static int audio_set_endpoint_req(struct usb_function *f,
 		const struct usb_ctrlrequest *ctrl)
 {
 	struct usb_composite_dev *cdev = f->config->cdev;
 	int			value = -EOPNOTSUPP;
 	u16			ep = le16_to_cpu(ctrl->wIndex);
 	u16			len = le16_to_cpu(ctrl->wLength);
 	u16			w_value = le16_to_cpu(ctrl->wValue);

 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
 			ctrl->bRequest, w_value, len, ep);

 	switch (ctrl->bRequest) {
 	case UAC_SET_CUR:
 		value = len;
 		break;

 	case UAC_SET_MIN:
 		break;

 	case UAC_SET_MAX:
 		break;

 	case UAC_SET_RES:
 		break;

 	case UAC_SET_MEM:
 		break;

 	default:
 		break;
 	}

 	return value;
 }

 static int audio_get_endpoint_req(struct usb_function *f,
 		const struct usb_ctrlrequest *ctrl)
 {
 	struct usb_composite_dev *cdev = f->config->cdev;
 	int value = -EOPNOTSUPP;
 	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
 	u16 len = le16_to_cpu(ctrl->wLength);
 	u16 w_value = le16_to_cpu(ctrl->wValue);

 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
 			ctrl->bRequest, w_value, len, ep);

 	switch (ctrl->bRequest) {
 	case UAC_GET_CUR:
 	case UAC_GET_MIN:
 	case UAC_GET_MAX:
 	case UAC_GET_RES:
 		value = len;
 		break;
 	case UAC_GET_MEM:
 		break;
 	default:
 		break;
 	}

 	return value;
 }

 static int
 f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 {
 	struct usb_composite_dev *cdev = f->config->cdev;
 	struct usb_request	*req = cdev->req;
 	int			value = -EOPNOTSUPP;
 	u16			w_index = le16_to_cpu(ctrl->wIndex);
 	u16			w_value = le16_to_cpu(ctrl->wValue);
 	u16			w_length = le16_to_cpu(ctrl->wLength);

 	/* composite driver infrastructure handles everything; interface
 	 * activation uses set_alt().
 	 */
 	switch (ctrl->bRequestType) {
 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
 		value = audio_set_intf_req(f, ctrl);
 		break;

 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
 		value = audio_get_intf_req(f, ctrl);
 		break;

 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
 		value = audio_set_endpoint_req(f, ctrl);
 		break;

 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
 		value = audio_get_endpoint_req(f, ctrl);
 		break;

 	default:
 		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 			ctrl->bRequestType, ctrl->bRequest,
 			w_value, w_index, w_length);
 	}

 	/* respond with data transfer or status phase? */
 	if (value >= 0) {
 		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
 			ctrl->bRequestType, ctrl->bRequest,
 			w_value, w_index, w_length);
 		req->zero = 0;
 		req->length = value;
 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 		if (value < 0)
 			ERROR(cdev, "audio response on err %d\n", value);
 	}

 	/* device either stalls (value < 0) or reports success */
 	return value;
 }

 static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 {
 	struct f_audio		*audio = func_to_audio(f);
 	struct usb_composite_dev *cdev = f->config->cdev;
 	struct usb_ep *out_ep = audio->out_ep;
 	struct usb_request *req;
 	int i = 0, err = 0;

 	DBG(cdev, "intf %d, alt %d\n", intf, alt);

 	if (intf == 1) {
 		if (alt == 1) {
 			usb_ep_enable(out_ep);
 			out_ep->driver_data = audio;
 			audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
 			if (IS_ERR(audio->copy_buf))
 				return -ENOMEM;

 			/*
 			 * allocate a bunch of read buffers
 			 * and queue them all at once.
 			 */
 			for (i = 0; i < req_count && err == 0; i++) {
 				req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
 				if (req) {
 					req->buf = kzalloc(req_buf_size,
 							GFP_ATOMIC);
 					if (req->buf) {
 						req->length = req_buf_size;
 						req->context = audio;
 						req->complete =
 							f_audio_complete;
 						err = usb_ep_queue(out_ep,
 							req, GFP_ATOMIC);
 						if (err)
 							ERROR(cdev,
 							"%s queue req: %d\n",
 							out_ep->name, err);
 					} else
 						err = -ENOMEM;
 				} else
 					err = -ENOMEM;
 			}

 		} else {
 			struct f_audio_buf *copy_buf = audio->copy_buf;
 			if (copy_buf) {
 				list_add_tail(&copy_buf->list,
 						&audio->play_queue);
 				schedule_work(&audio->playback_work);
 			}
 		}
 	}

 	return err;
 }

 static void f_audio_disable(struct usb_function *f)
 {
 	return;
 }

 /*-------------------------------------------------------------------------*/

 static void f_audio_build_desc(struct f_audio *audio)
 {
 	struct gaudio *card = &audio->card;
 	u8 *sam_freq;
 	int rate;

 	/* Set channel numbers */
 	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
 	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);

 	/* Set sample rates */
 	rate = u_audio_get_playback_rate(card);
 	sam_freq = as_type_i_desc.tSamFreq[0];
 	memcpy(sam_freq, &rate, 3);

 	/* Todo: Set Sample bits and other parameters */

 	return;
 }

 /* audio function driver setup/binding */
 static int __init
 f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_composite_dev *cdev = c->cdev;
 	struct f_audio		*audio = func_to_audio(f);
 	int			status;
 	struct usb_ep		*ep = NULL;

 	f_audio_build_desc(audio);

 	/* allocate instance-specific interface IDs, and patch descriptors */
 	status = usb_interface_id(c, f);
 	if (status < 0)
 		goto fail;
 	ac_interface_desc.bInterfaceNumber = status;

 	status = usb_interface_id(c, f);
 	if (status < 0)
 		goto fail;
 	as_interface_alt_0_desc.bInterfaceNumber = status;
 	as_interface_alt_1_desc.bInterfaceNumber = status;

 	status = -ENODEV;

 	/* allocate instance-specific endpoints */
 	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
 	if (!ep)
 		goto fail;
 	audio->out_ep = ep;
 	audio->out_ep->desc = &as_out_ep_desc;
 	ep->driver_data = cdev;	/* claim */

 	status = -ENOMEM;

 	/* copy descriptors, and track endpoint copies */
 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL);
 	if (status)
 		goto fail;
 	return 0;

 fail:
 	if (ep)
 		ep->driver_data = NULL;
 	return status;
 }

 static void
 f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_audio		*audio = func_to_audio(f);

 	usb_free_all_descriptors(f);
 	kfree(audio);
 }

 /*-------------------------------------------------------------------------*/

 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
 {
 	con->data[cmd] = value;

 	return 0;
 }

 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
 {
 	return con->data[cmd];
 }

 /* Todo: add more control selecotor dynamically */
 static int __init control_selector_init(struct f_audio *audio)
 {
 	INIT_LIST_HEAD(&audio->cs);
 	list_add(&feature_unit.list, &audio->cs);

 	INIT_LIST_HEAD(&feature_unit.control);
 	list_add(&mute_control.list, &feature_unit.control);
 	list_add(&volume_control.list, &feature_unit.control);

 	volume_control.data[UAC__CUR] = 0xffc0;
 	volume_control.data[UAC__MIN] = 0xe3a0;
 	volume_control.data[UAC__MAX] = 0xfff0;
 	volume_control.data[UAC__RES] = 0x0030;

 	return 0;
 }

 /**
  * audio_bind_config - add USB audio function to a configuration
  * @c: the configuration to supcard the USB audio function
  * Context: single threaded during gadget setup
  *
  * Returns zero on success, else negative errno.
  */
 static int __init audio_bind_config(struct usb_configuration *c)
 {
 	struct f_audio *audio;
 	int status;

 	/* allocate and initialize one new instance */
 	audio = kzalloc(sizeof *audio, GFP_KERNEL);
 	if (!audio)
 		return -ENOMEM;

 	audio->card.func.name = "g_audio";
 	audio->card.gadget = c->cdev->gadget;

 	INIT_LIST_HEAD(&audio->play_queue);
 	spin_lock_init(&audio->lock);

 	/* set up ASLA audio devices */
 	status = gaudio_setup(&audio->card);
 	if (status < 0)
 		goto setup_fail;

 	audio->card.func.strings = audio_strings;
 	audio->card.func.bind = f_audio_bind;
 	audio->card.func.unbind = f_audio_unbind;
 	audio->card.func.set_alt = f_audio_set_alt;
 	audio->card.func.setup = f_audio_setup;
 	audio->card.func.disable = f_audio_disable;

 	control_selector_init(audio);

 	INIT_WORK(&audio->playback_work, f_audio_playback_work);

 	status = usb_add_function(c, &audio->card.func);
 	if (status)
 		goto add_fail;

 	INFO(c->cdev, "audio_buf_size %d, req_buf_size %d, req_count %d\n",
 		audio_buf_size, req_buf_size, req_count);

 	return status;

 add_fail:
 	gaudio_cleanup();
 setup_fail:
 	kfree(audio);
 	return status;
 }
	/*
	* f_audio.c -- USB Audio class function driver
	*
	* Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
	* Copyright (C) 2008 Analog Devices, Inc
	*
	* Enter bugs at http://blackfin.uclinux.org/
	*
	* Licensed under the GPL-2 or later.
	*/

	#include <linux/slab.h>
	#include <linux/kernel.h>
	#include <linux/device.h>
	#include <linux/atomic.h>

	#include "u_uac1.h"

	#define OUT_EP_MAX_PACKET_SIZE 200
	static int req_buf_size = OUT_EP_MAX_PACKET_SIZE;
	module_param(req_buf_size, int, S_IRUGO);
	MODULE_PARM_DESC(req_buf_size, "ISO OUT endpoint request buffer size");

	static int req_count = 256;
	module_param(req_count, int, S_IRUGO);
	MODULE_PARM_DESC(req_count, "ISO OUT endpoint request count");

	static int audio_buf_size = 48000;
	module_param(audio_buf_size, int, S_IRUGO);
	MODULE_PARM_DESC(audio_buf_size, "Audio buffer size");

	static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
	static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);

	/*
	* DESCRIPTORS ... most are static, but strings and full
	* configuration descriptors are built on demand.
	*/

	/*
	* We have two interfaces- AudioControl and AudioStreaming
	* TODO: only supcard playback currently
	*/
	#define F_AUDIO_AC_INTERFACE 0
	#define F_AUDIO_AS_INTERFACE 1
	#define F_AUDIO_NUM_INTERFACES 2

	/* B.3.1 Standard AC Interface Descriptor */
	static struct usb_interface_descriptor ac_interface_desc __initdata = {
	.bLength = USB_DT_INTERFACE_SIZE,
	.bDescriptorType = USB_DT_INTERFACE,
	.bNumEndpoints = 0,
	.bInterfaceClass = USB_CLASS_AUDIO,
	.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL,
	};

	DECLARE_UAC_AC_HEADER_DESCRIPTOR(2);

	#define UAC_DT_AC_HEADER_LENGTH UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
	/* 1 input terminal, 1 output terminal and 1 feature unit */
	#define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
	/* B.3.2 Class-Specific AC Interface Descriptor */
	static struct uac1_ac_header_descriptor_2 ac_header_desc = {
	.bLength = UAC_DT_AC_HEADER_LENGTH,
	.bDescriptorType = USB_DT_CS_INTERFACE,
	.bDescriptorSubtype = UAC_HEADER,
	.bcdADC = __constant_cpu_to_le16(0x0100),
	.wTotalLength = __constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
	.bInCollection = F_AUDIO_NUM_INTERFACES,
	.baInterfaceNr = {
	[0] = F_AUDIO_AC_INTERFACE,
	[1] = F_AUDIO_AS_INTERFACE,
	}
	};

	#define INPUT_TERMINAL_ID 1
	static struct uac_input_terminal_descriptor input_terminal_desc = {
	.bLength = UAC_DT_INPUT_TERMINAL_SIZE,
	.bDescriptorType = USB_DT_CS_INTERFACE,
	.bDescriptorSubtype = UAC_INPUT_TERMINAL,
	.bTerminalID = INPUT_TERMINAL_ID,
	.wTerminalType = UAC_TERMINAL_STREAMING,
	.bAssocTerminal = 0,
	.wChannelConfig = 0x3,
	};

	DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);

	#define FEATURE_UNIT_ID 2
	static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
	.bLength = UAC_DT_FEATURE_UNIT_SIZE(0),
	.bDescriptorType = USB_DT_CS_INTERFACE,
	.bDescriptorSubtype = UAC_FEATURE_UNIT,
	.bUnitID = FEATURE_UNIT_ID,
	.bSourceID = INPUT_TERMINAL_ID,
	.bControlSize = 2,
	.bmaControls[0] = (UAC_FU_MUTE \| UAC_FU_VOLUME),
	};

	static struct usb_audio_control mute_control = {
	.list = LIST_HEAD_INIT(mute_control.list),
	.name = "Mute Control",
	.type = UAC_FU_MUTE,
	/* Todo: add real Mute control code */
	.set = generic_set_cmd,
	.get = generic_get_cmd,
	};

	static struct usb_audio_control volume_control = {
	.list = LIST_HEAD_INIT(volume_control.list),
	.name = "Volume Control",
	.type = UAC_FU_VOLUME,
	/* Todo: add real Volume control code */
	.set = generic_set_cmd,
	.get = generic_get_cmd,
	};

	static struct usb_audio_control_selector feature_unit = {
	.list = LIST_HEAD_INIT(feature_unit.list),
	.id = FEATURE_UNIT_ID,
	.name = "Mute & Volume Control",
	.type = UAC_FEATURE_UNIT,
	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
	};

	#define OUTPUT_TERMINAL_ID 3
	static struct uac1_output_terminal_descriptor output_terminal_desc = {
	.bLength = UAC_DT_OUTPUT_TERMINAL_SIZE,
	.bDescriptorType = USB_DT_CS_INTERFACE,
	.bDescriptorSubtype = UAC_OUTPUT_TERMINAL,
	.bTerminalID = OUTPUT_TERMINAL_ID,
	.wTerminalType = UAC_OUTPUT_TERMINAL_SPEAKER,
	.bAssocTerminal = FEATURE_UNIT_ID,
	.bSourceID = FEATURE_UNIT_ID,
	};

	/* B.4.1 Standard AS Interface Descriptor */
	static struct usb_interface_descriptor as_interface_alt_0_desc = {
	.bLength = USB_DT_INTERFACE_SIZE,
	.bDescriptorType = USB_DT_INTERFACE,
	.bAlternateSetting = 0,
	.bNumEndpoints = 0,
	.bInterfaceClass = USB_CLASS_AUDIO,
	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
	};

	static struct usb_interface_descriptor as_interface_alt_1_desc = {
	.bLength = USB_DT_INTERFACE_SIZE,
	.bDescriptorType = USB_DT_INTERFACE,
	.bAlternateSetting = 1,
	.bNumEndpoints = 1,
	.bInterfaceClass = USB_CLASS_AUDIO,
	.bInterfaceSubClass = USB_SUBCLASS_AUDIOSTREAMING,
	};

	/* B.4.2 Class-Specific AS Interface Descriptor */
	static struct uac1_as_header_descriptor as_header_desc = {
	.bLength = UAC_DT_AS_HEADER_SIZE,
	.bDescriptorType = USB_DT_CS_INTERFACE,
	.bDescriptorSubtype = UAC_AS_GENERAL,
	.bTerminalLink = INPUT_TERMINAL_ID,
	.bDelay = 1,
	.wFormatTag = UAC_FORMAT_TYPE_I_PCM,
	};

	DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);

	static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
	.bLength = UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
	.bDescriptorType = USB_DT_CS_INTERFACE,
	.bDescriptorSubtype = UAC_FORMAT_TYPE,
	.bFormatType = UAC_FORMAT_TYPE_I,
	.bSubframeSize = 2,
	.bBitResolution = 16,
	.bSamFreqType = 1,
	};

	/* Standard ISO OUT Endpoint Descriptor */
	static struct usb_endpoint_descriptor as_out_ep_desc = {
	.bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = USB_DIR_OUT,
	.bmAttributes = USB_ENDPOINT_SYNC_ADAPTIVE
	\| USB_ENDPOINT_XFER_ISOC,
	.wMaxPacketSize = __constant_cpu_to_le16(OUT_EP_MAX_PACKET_SIZE),
	.bInterval = 4,
	};

	/* Class-specific AS ISO OUT Endpoint Descriptor */
	static struct uac_iso_endpoint_descriptor as_iso_out_desc __initdata = {
	.bLength = UAC_ISO_ENDPOINT_DESC_SIZE,
	.bDescriptorType = USB_DT_CS_ENDPOINT,
	.bDescriptorSubtype = UAC_EP_GENERAL,
	.bmAttributes = 1,
	.bLockDelayUnits = 1,
	.wLockDelay = __constant_cpu_to_le16(1),
	};

	static struct usb_descriptor_header *f_audio_desc[] __initdata = {
	(struct usb_descriptor_header *)&ac_interface_desc,
	(struct usb_descriptor_header *)&ac_header_desc,

	(struct usb_descriptor_header *)&input_terminal_desc,
	(struct usb_descriptor_header *)&output_terminal_desc,
	(struct usb_descriptor_header *)&feature_unit_desc,

	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
	(struct usb_descriptor_header *)&as_header_desc,

	(struct usb_descriptor_header *)&as_type_i_desc,

	(struct usb_descriptor_header *)&as_out_ep_desc,
	(struct usb_descriptor_header *)&as_iso_out_desc,
	NULL,
	};

	/*
	* This function is an ALSA sound card following USB Audio Class Spec 1.0.
	*/

	/-------------------------------------------------------------------------/
	struct f_audio_buf {
	u8 *buf;
	int actual;
	struct list_head list;
	};

	static struct f_audio_buf *f_audio_buffer_alloc(int buf_size)
	{
	struct f_audio_buf *copy_buf;

	copy_buf = kzalloc(sizeof *copy_buf, GFP_ATOMIC);
	if (!copy_buf)
	return ERR_PTR(-ENOMEM);

	copy_buf->buf = kzalloc(buf_size, GFP_ATOMIC);
	if (!copy_buf->buf) {
	kfree(copy_buf);
	return ERR_PTR(-ENOMEM);
	}

	return copy_buf;
	}

	static void f_audio_buffer_free(struct f_audio_buf *audio_buf)
	{
	kfree(audio_buf->buf);
	kfree(audio_buf);
	}
	/-------------------------------------------------------------------------/

	struct f_audio {
	struct gaudio card;

	/* endpoints handle full and/or high speeds */
	struct usb_ep *out_ep;

	spinlock_t lock;
	struct f_audio_buf *copy_buf;
	struct work_struct playback_work;
	struct list_head play_queue;

	/* Control Set command */
	struct list_head cs;
	u8 set_cmd;
	struct usb_audio_control *set_con;
	};

	static inline struct f_audio func_to_audio(struct usb_function f)
	{
	return container_of(f, struct f_audio, card.func);
	}

	/-------------------------------------------------------------------------/

	static void f_audio_playback_work(struct work_struct *data)
	{
	struct f_audio *audio = container_of(data, struct f_audio,
	playback_work);
	struct f_audio_buf *play_buf;

	spin_lock_irq(&audio->lock);
	if (list_empty(&audio->play_queue)) {
	spin_unlock_irq(&audio->lock);
	return;
	}
	play_buf = list_first_entry(&audio->play_queue,
	struct f_audio_buf, list);
	list_del(&play_buf->list);
	spin_unlock_irq(&audio->lock);

	u_audio_playback(&audio->card, play_buf->buf, play_buf->actual);
	f_audio_buffer_free(play_buf);
	}

	static int f_audio_out_ep_complete(struct usb_ep ep, struct usb_request req)
	{
	struct f_audio *audio = req->context;
	struct usb_composite_dev *cdev = audio->card.func.config->cdev;
	struct f_audio_buf *copy_buf = audio->copy_buf;
	int err;

	if (!copy_buf)
	return -EINVAL;

	/* Copy buffer is full, add it to the play_queue */
	if (audio_buf_size - copy_buf->actual < req->actual) {
	list_add_tail(&copy_buf->list, &audio->play_queue);
	schedule_work(&audio->playback_work);
	copy_buf = f_audio_buffer_alloc(audio_buf_size);
	if (IS_ERR(copy_buf))
	return -ENOMEM;
	}

	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
	copy_buf->actual += req->actual;
	audio->copy_buf = copy_buf;

	err = usb_ep_queue(ep, req, GFP_ATOMIC);
	if (err)
	ERROR(cdev, "%s queue req: %d\n", ep->name, err);

	return 0;

	}

	static void f_audio_complete(struct usb_ep ep, struct usb_request req)
	{
	struct f_audio *audio = req->context;
	int status = req->status;
	u32 data = 0;
	struct usb_ep *out_ep = audio->out_ep;

	switch (status) {

	case 0: /* normal completion? */
	if (ep == out_ep)
	f_audio_out_ep_complete(ep, req);
	else if (audio->set_con) {
	memcpy(&data, req->buf, req->length);
	audio->set_con->set(audio->set_con, audio->set_cmd,
	le16_to_cpu(data));
	audio->set_con = NULL;
	}
	break;
	default:
	break;
	}
	}

	static int audio_set_intf_req(struct usb_function *f,
	const struct usb_ctrlrequest *ctrl)
	{
	struct f_audio *audio = func_to_audio(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct usb_request *req = cdev->req;
	u8 id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
	u16 len = le16_to_cpu(ctrl->wLength);
	u16 w_value = le16_to_cpu(ctrl->wValue);
	u8 con_sel = (w_value >> 8) & 0xFF;
	u8 cmd = (ctrl->bRequest & 0x0F);
	struct usb_audio_control_selector *cs;
	struct usb_audio_control *con;

	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
	ctrl->bRequest, w_value, len, id);

	list_for_each_entry(cs, &audio->cs, list) {
	if (cs->id == id) {
	list_for_each_entry(con, &cs->control, list) {
	if (con->type == con_sel) {
	audio->set_con = con;
	break;
	}
	}
	break;
	}
	}

	audio->set_cmd = cmd;
	req->context = audio;
	req->complete = f_audio_complete;

	return len;
	}

	static int audio_get_intf_req(struct usb_function *f,
	const struct usb_ctrlrequest *ctrl)
	{
	struct f_audio *audio = func_to_audio(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct usb_request *req = cdev->req;
	int value = -EOPNOTSUPP;
	u8 id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
	u16 len = le16_to_cpu(ctrl->wLength);
	u16 w_value = le16_to_cpu(ctrl->wValue);
	u8 con_sel = (w_value >> 8) & 0xFF;
	u8 cmd = (ctrl->bRequest & 0x0F);
	struct usb_audio_control_selector *cs;
	struct usb_audio_control *con;

	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
	ctrl->bRequest, w_value, len, id);

	list_for_each_entry(cs, &audio->cs, list) {
	if (cs->id == id) {
	list_for_each_entry(con, &cs->control, list) {
	if (con->type == con_sel && con->get) {
	value = con->get(con, cmd);
	break;
	}
	}
	break;
	}
	}

	req->context = audio;
	req->complete = f_audio_complete;
	len = min_t(size_t, sizeof(value), len);
	memcpy(req->buf, &value, len);

	return len;
	}

	static int audio_set_endpoint_req(struct usb_function *f,
	const struct usb_ctrlrequest *ctrl)
	{
	struct usb_composite_dev *cdev = f->config->cdev;
	int value = -EOPNOTSUPP;
	u16 ep = le16_to_cpu(ctrl->wIndex);
	u16 len = le16_to_cpu(ctrl->wLength);
	u16 w_value = le16_to_cpu(ctrl->wValue);

	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
	ctrl->bRequest, w_value, len, ep);

	switch (ctrl->bRequest) {
	case UAC_SET_CUR:
	value = len;
	break;

	case UAC_SET_MIN:
	break;

	case UAC_SET_MAX:
	break;

	case UAC_SET_RES:
	break;

	case UAC_SET_MEM:
	break;

	default:
	break;
	}

	return value;
	}

	static int audio_get_endpoint_req(struct usb_function *f,
	const struct usb_ctrlrequest *ctrl)
	{
	struct usb_composite_dev *cdev = f->config->cdev;
	int value = -EOPNOTSUPP;
	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
	u16 len = le16_to_cpu(ctrl->wLength);
	u16 w_value = le16_to_cpu(ctrl->wValue);

	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
	ctrl->bRequest, w_value, len, ep);

	switch (ctrl->bRequest) {
	case UAC_GET_CUR:
	case UAC_GET_MIN:
	case UAC_GET_MAX:
	case UAC_GET_RES:
	value = len;
	break;
	case UAC_GET_MEM:
	break;
	default:
	break;
	}

	return value;
	}

	static int
	f_audio_setup(struct usb_function f, const struct usb_ctrlrequest ctrl)
	{
	struct usb_composite_dev *cdev = f->config->cdev;
	struct usb_request *req = cdev->req;
	int value = -EOPNOTSUPP;
	u16 w_index = le16_to_cpu(ctrl->wIndex);
	u16 w_value = le16_to_cpu(ctrl->wValue);
	u16 w_length = le16_to_cpu(ctrl->wLength);

	/* composite driver infrastructure handles everything; interface
	* activation uses set_alt().
	*/
	switch (ctrl->bRequestType) {
	case USB_DIR_OUT \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE:
	value = audio_set_intf_req(f, ctrl);
	break;

	case USB_DIR_IN \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE:
	value = audio_get_intf_req(f, ctrl);
	break;

	case USB_DIR_OUT \| USB_TYPE_CLASS \| USB_RECIP_ENDPOINT:
	value = audio_set_endpoint_req(f, ctrl);
	break;

	case USB_DIR_IN \| USB_TYPE_CLASS \| USB_RECIP_ENDPOINT:
	value = audio_get_endpoint_req(f, ctrl);
	break;

	default:
	ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
	ctrl->bRequestType, ctrl->bRequest,
	w_value, w_index, w_length);
	}

	/* respond with data transfer or status phase? */
	if (value >= 0) {
	DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
	ctrl->bRequestType, ctrl->bRequest,
	w_value, w_index, w_length);
	req->zero = 0;
	req->length = value;
	value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
	if (value < 0)
	ERROR(cdev, "audio response on err %d\n", value);
	}

	/* device either stalls (value < 0) or reports success */
	return value;
	}

	static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
	{
	struct f_audio *audio = func_to_audio(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct usb_ep *out_ep = audio->out_ep;
	struct usb_request *req;
	int i = 0, err = 0;

	DBG(cdev, "intf %d, alt %d\n", intf, alt);

	if (intf == 1) {
	if (alt == 1) {
	usb_ep_enable(out_ep);
	out_ep->driver_data = audio;
	audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
	if (IS_ERR(audio->copy_buf))
	return -ENOMEM;

	/*
	* allocate a bunch of read buffers
	* and queue them all at once.
	*/
	for (i = 0; i < req_count && err == 0; i++) {
	req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
	if (req) {
	req->buf = kzalloc(req_buf_size,
	GFP_ATOMIC);
	if (req->buf) {
	req->length = req_buf_size;
	req->context = audio;
	req->complete =
	f_audio_complete;
	err = usb_ep_queue(out_ep,
	req, GFP_ATOMIC);
	if (err)
	ERROR(cdev,
	"%s queue req: %d\n",
	out_ep->name, err);
	} else
	err = -ENOMEM;
	} else
	err = -ENOMEM;
	}

	} else {
	struct f_audio_buf *copy_buf = audio->copy_buf;
	if (copy_buf) {
	list_add_tail(&copy_buf->list,
	&audio->play_queue);
	schedule_work(&audio->playback_work);
	}
	}
	}

	return err;
	}

	static void f_audio_disable(struct usb_function *f)
	{
	return;
	}

	/-------------------------------------------------------------------------/

	static void f_audio_build_desc(struct f_audio *audio)
	{
	struct gaudio *card = &audio->card;
	u8 *sam_freq;
	int rate;

	/* Set channel numbers */
	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);

	/* Set sample rates */
	rate = u_audio_get_playback_rate(card);
	sam_freq = as_type_i_desc.tSamFreq[0];
	memcpy(sam_freq, &rate, 3);

	/* Todo: Set Sample bits and other parameters */

	return;
	}

	/* audio function driver setup/binding */
	static int __init
	f_audio_bind(struct usb_configuration c, struct usb_function f)
	{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_audio *audio = func_to_audio(f);
	int status;
	struct usb_ep *ep = NULL;

	f_audio_build_desc(audio);

	/* allocate instance-specific interface IDs, and patch descriptors */
	status = usb_interface_id(c, f);
	if (status < 0)
	goto fail;
	ac_interface_desc.bInterfaceNumber = status;

	status = usb_interface_id(c, f);
	if (status < 0)
	goto fail;
	as_interface_alt_0_desc.bInterfaceNumber = status;
	as_interface_alt_1_desc.bInterfaceNumber = status;

	status = -ENODEV;

	/* allocate instance-specific endpoints */
	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
	if (!ep)
	goto fail;
	audio->out_ep = ep;
	audio->out_ep->desc = &as_out_ep_desc;
	ep->driver_data = cdev; /* claim */

	status = -ENOMEM;

	/* copy descriptors, and track endpoint copies */
	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL);
	if (status)
	goto fail;
	return 0;

	fail:
	if (ep)
	ep->driver_data = NULL;
	return status;
	}

	static void
	f_audio_unbind(struct usb_configuration c, struct usb_function f)
	{
	struct f_audio *audio = func_to_audio(f);

	usb_free_all_descriptors(f);
	kfree(audio);
	}

	/-------------------------------------------------------------------------/

	static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
	{
	con->data[cmd] = value;

	return 0;
	}

	static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
	{
	return con->data[cmd];
	}

	/* Todo: add more control selecotor dynamically */
	static int __init control_selector_init(struct f_audio *audio)
	{
	INIT_LIST_HEAD(&audio->cs);
	list_add(&feature_unit.list, &audio->cs);

	INIT_LIST_HEAD(&feature_unit.control);
	list_add(&mute_control.list, &feature_unit.control);
	list_add(&volume_control.list, &feature_unit.control);

	volume_control.data[UAC__CUR] = 0xffc0;
	volume_control.data[UAC__MIN] = 0xe3a0;
	volume_control.data[UAC__MAX] = 0xfff0;
	volume_control.data[UAC__RES] = 0x0030;

	return 0;
	}

	/**
	* audio_bind_config - add USB audio function to a configuration
	* @c: the configuration to supcard the USB audio function
	* Context: single threaded during gadget setup
	*
	* Returns zero on success, else negative errno.
	*/
	static int __init audio_bind_config(struct usb_configuration *c)
	{
	struct f_audio *audio;
	int status;

	/* allocate and initialize one new instance */
	audio = kzalloc(sizeof *audio, GFP_KERNEL);
	if (!audio)
	return -ENOMEM;

	audio->card.func.name = "g_audio";
	audio->card.gadget = c->cdev->gadget;

	INIT_LIST_HEAD(&audio->play_queue);
	spin_lock_init(&audio->lock);

	/* set up ASLA audio devices */
	status = gaudio_setup(&audio->card);
	if (status < 0)
	goto setup_fail;

	audio->card.func.strings = audio_strings;
	audio->card.func.bind = f_audio_bind;
	audio->card.func.unbind = f_audio_unbind;
	audio->card.func.set_alt = f_audio_set_alt;
	audio->card.func.setup = f_audio_setup;
	audio->card.func.disable = f_audio_disable;

	control_selector_init(audio);

	INIT_WORK(&audio->playback_work, f_audio_playback_work);

	status = usb_add_function(c, &audio->card.func);
	if (status)
	goto add_fail;

	INFO(c->cdev, "audio_buf_size %d, req_buf_size %d, req_count %d\n",
	audio_buf_size, req_buf_size, req_count);

	return status;

	add_fail:
	gaudio_cleanup();
	setup_fail:
	kfree(audio);
	return status;
	}